A Path Computation Element (PCE) is an entity that is capable of computing a network path or route based on a network topology, and applying computational constraints to the computation. The capability of a PCE to compute different types of paths allows a PCE to provide traffic engineering functions.
Constraint-based path computation is a fundamental building block for traffic engineering networks. However, in these kind of networks, path computation is complex, and may require special computational components and cooperation between different network domains.
A PCE-based network architecture defines PCEs to perform computations of a multi-layer path, and take constraints into consideration. A multi-layer network may be considered as distinct path computation regions within a PCE domain, and therefore, a PCE-based architecture is useful to allow path computation from one layer network region, across the multi-layer network, to another layer network region. A PCE may be placed on a single network node with high processing capabilities, or several PCEs may be deployed on nodes across a network.
A distributed PCE model may refer to a domain or network that may include multiple PCEs, and where computations of paths are shared among the PCEs. A given path may in turn be computed by a single, or multiple PCEs. A PCE agent may be linked to a particular PCE or may be able to choose freely among several PCEs.
To address the complexity of path computations in multi-layer networks, there is a need for a PCE-based system in multi-layer networks, which provides efficient, correct and optimal path computations.